Iran's nuclear programme

A thousand and one excuses

But they are running out

IS IRAN trying to build a bomb, or is its nuclear work aimed merely at keeping the lights on? Gathering evidence, and Iran's refusal to heed a string of UN Security Council resolutions and stop its suspect activities, make the question seem quaint.

Few believe the tales Iranian officials have spun since the first news, in 2002, of their covert efforts to enrich uranium—usable for civilian nuclear reactors, but abusable at high enrichment for making weapons. Yet even the recent discovery of another hitherto secret enrichment plant being built deep in a mountainside on a heavily guarded military compound near the city of Qom had a ready explanation: to keep “civilian” enrichment going if other nuclear sites were attacked.

A steady leak of documents in recent months appears to tell a compelling story at odds with Iran's version. A memo published in Britain by the Times, if authentic, shows Iran in 2007 about to embark on a four-year set of experiments, picking up on related past work, to develop a neutron initiator, or bomb trigger, containing uranium deuteride, or UD3 (a compound used by Pakistan in its bombs). The actual tests, however, would be done with substances less likely to be detected by inspectors from the International Atomic Energy Agency (IAEA), the UN's nuclear guardian.

Some, like Russia's prime minister, Vladimir Putin, have hitherto complained that, for all Iran's odd behaviour, there is no hard evidence it is after a bomb. The experiments reported in the Times have no other purpose. Iranian officials dismiss these and other documents as forgeries, yet refuse inspectors access to scientists in Iran who could answer their questions.

Publicly, IAEA inspectors say they cannot confirm that Iran's nuclear programme is entirely peaceful. Behind closed doors, they reportedly judge it has mastered the skills it would need to build a nuclear weapon. They have had the report about neutron initiators for some time, part of a trove of documents collected from different governments. These describe weapons-related design work and other experiments, as well as the organisational structure of Iran's military effort.

The IAEA says much of this material is credible and consistent. Critics, however, hark back to a controversial 2007 American National Intelligence Estimate that concluded Iran had indeed had a warhead-building programme but ended it in 2003. The British, French and German intelligence services soon let it be known they thought work had resumed; Israel's spies say it never stopped. It may have started again by late 2005, after Iran's fiery president, Mahmoud Ahmadinejad, took office.

Meanwhile, Iran continues to enrich uranium. After months of intensified efforts to coax it into talks, diplomats from America, Britain, France, Germany, Russia and China look like starting 2010 in discussions about tougher sanctions instead. And Iran's evasive tactics, combined with the threats issued periodically by Mr Ahmadinejad and Iran's latest test of its 2,000km Sejjil missile on December 16th, will ensure that Israel in particular keeps “all options” on the table for dealing with Iran's defiance.